Project Summary Access to various contraceptive methods and associated laws on parental consent have changed over time and across states in the U.S. In particular, progestin-only emergency contraception (EC)?also known by the brand name Plan B?has been subject to changing access laws at both the state and federal levels. The most significant change in access to EC since its release was its FDA approval as an over-the-counter (OTC) medication in 2006, where previously it had been available by prescription only. Improving ease of access to Plan B may have a substantial impact on both EC uptake and efficacy. Previous research has had limited follow-up, used data that lacked the appropriate denominators, and was largely unable to measure the uptake of EC; such research also did not examine differences by race and ethnicity, in particular among Hispanic women and non-Hispanic Black women. For multiple socioeconomic reasons, visiting a physician to obtain a prescription for EC may present differential barriers to access for these populations. Thus, there is a critical need to understand the impact of OTC access to EC on uptake and pregnancy and birth rates. Our objective is to meet this critical need by studying the impact of the 2006 approval of Plan B. Based on our preliminary data analyses, the central hypothesis is that increased access to EC because of OTC availability will result in increased uptake and lower pregnancy and birth rates. This project will use data from three data sources?the Nielsen Consumer Panel, American Community Survey, and Behavioral Risk Factor Surveillance System?to address the following specific aims: (1) measure the effect of OTC availability of EC on uptake and overall pregnancy and birth rates, and (2) measure the differential impact of OTC availability of EC on pregnancy and birth rates among racial/ethnic groups that are most likely to have unintended pregnancies?Hispanic women, non-Hispanic Black women, and teenagers. Using these three data sources, we will conduct difference-in- differences analyses to study the outcomes of interest. This research is innovative because it uses data sources that allow us to examine the long-term impact of increased access to EC using detailed, individual- level data. It is also the first study to examine differences by race and ethnicity. The proposed research is significant because it will shed light on the effect of increased access to EC on the rate of unintended pregnancy; unintended pregnancies resulting in births are associated with poorer maternal and infant health outcomes, impacts on physical and mental health, and negative economic outcomes. This research will benefit vulnerable minority populations and promote public health by providing evidence on a simple policy tool (improved access to EC) that may have a substantial impact on reducing unintended pregnancy.